Battery modules are installed on an electric vehicle or a hybrid electric vehicle that uses a motor as a drive source. For example, Patent Literature 1 discloses a vehicle in which battery modules are installed in a space defined underneath a luggage compartment.
Vehicles of this type include a battery cooling unit for holding the temperature of a battery within a proper temperature range to prevent the deterioration in performance of the battery which would be caused by an abnormal increase in temperature of the battery. For example, in the vehicle described in Patent Literature 1 above, the battery is cooled by air that is taken in from the passenger compartment, and the air, which has been used to cool the battery, is then separately let out to the outside of the vehicle and into the space defined underneath the luggage compartment. The exhaust air that is discharged into the space underneath the luggage compartment is designed to be returned to the passenger compartment through exhaust air passage holes that are formed in a partition panel that separates the passenger compartment from the luggage compartment.